Monday, September 21, 2009

Hope everyone is enjoying the summer extension. New El Nino update out this morning. If you take the the four regions: Nino 1+2, 3, 3-4, & 4, as the four legs El Nino stands on, then it just lost one. Nino 1+2 which had a temp of +1 in the beginning of August is now down to .3 after falling for the past month. Region 3 has fallen from 1 to .8 & held steady this week. The other two regions have held pretty steady at .9 & .8. The warming should be continuing in the Eastern Equatorial Pacific not reversing if El Nino is going to strengthen. Also, the SOI which should be going negative with a strengthening El Nino has been positive. The 30 & 90 day averages are both now over +2. http://www.longpaddock.qld.gov.au/SeasonalClimateOutlook/SouthernOscillationIndex/30DaySOIValues/

If the SOI continues positive & the SST's continue to cool, expect to see the models to continue to trend down the forecasted El Nino strength for this winter. Most have a peak now at 1.25 which is moderate. A handful have it decreasing starting now.

I hear a lot of people talking about a big winter coming, but no one seems to be able to answer why it's going to be a big winter. I have seen a few headlines about El Nino is coming. El Nino is here & currently weakening. The main impact of El Nino is to shift the storm track towards Southern California. Since we are in Central/Northern CA we have a record of 50/50 above & below average seasons in El Nino years. The good news is that the drought in CA should be aleviated somewhat this winter.

There are two reasons that I think we have a shot at a big winter, although neither are can be counted on as a lock for a big year. First, is the reasons I explained in my July 19th posting which I spent a lot of time researching. The conditions currently, with the recent reversal of the Pacific Ocean temp cycle to colder, with a weak "reactionary" El Nino, plus other factors, lines up best with winter of 51-52. MEI analogs show the same. That was a huge winter, but it has been 60 years since then so there is not a common recurrence to prove my theory.

The second reason I think we have a shot at a big winter is that statistically we are due. Check out the Donner Summit snowfall graph: http://thestormking.com/Weather/Sierra_Snowfall/sierra_snowfall.html . 3 times we went 9 or more years not breaking 40 feet: 1912-21 (10 years), 1923-31 (9 years), & 1984-92 (9 years). Last year made 11 in a row for the first time on this record. It is also the longest stretch of not breaking 45 ft. since 1912-35. It the longest stretch since 1907-35 of not hitting 50 ft, the last time we hit that was in 1996. It has been 57 years since we broke 60 ft., the last time was the winter of 1951-52. So the law of averages says we are due for a big year, even if it's not 60 ft. we would settle for 40 or better! BA

Oh, by the way, looking for a pattern change to colder the first week of October, possibly stormy by the second week....